Sensors are used in motor vehicles to detect various parameters and to transmit data to an analyzer unit. The sensors used include at least one sensitive module, which converts at least one physical and/or one chemical parameter, depending on a state relevant for operation of the vehicle, which may be into an electrical quantity. In addition, the sensors usually include a circuit for initial processing of the quantity thereby obtained and providing a sensor output signal, which may be digital, on a data transmitting unit.
The sensor output signal is transmitted from the data transmitting unit to an analyzer unit, e.g., to a control unit. This analyzer unit has at least one data receiving unit, which is connected via a suitable transmitting arrangement to the data transmitting unit of the sensor.
Information contained in the electrical quantities obtained internally in most sensors definitely exceeds the information demand for protecting certain applications. At the same time, the transmission path between sensors and control units, e.g., in the form of a peripheral sensor interface (PSI) having a transmission capacity of 125 kbps, constitutes a bottleneck in the flow of information.
For this reason, only a subset of the maximum available information is usually sent from the sensor to the control unit. However, care must be taken to ensure that the greatest possible amount of information relevant for the particular function that is to be implemented by the control unit or the connected systems does in fact reach the data receiving unit of the control unit. This is true to a particular extent when a sensor contains multiple sensitive modules or is even designed as a so-called combination sensor having sensitive modules for detecting different physical and/or chemical parameters.
It is therefore known that sensors may be equipped with an analyzer circuit, which essentially provides a data volume that has been processed according to fixed specifications to the data transmitting unit. To this end, the electrical output quantity of the sensitive module is applied to different circuit components which function as amplifiers, filters or other converters, for example, which may already perform complete digital data processing. These circuit components form a signal path between the sensitive module of the sensor and the data transmitting unit. If a signal travels along this signal path, components for a data word, which is applied to the data transmitting unit and may be retrieved for further processing outside of the sensor, are extracted from the output variable of the sensitive module in a fixedly predefined manner.
It is also known that a sensor may be equipped with several such signal paths, which are selected depending on the particular function to be implemented by the control unit and which differ with regard to the type and manner in which the data word applied to the data transmitting unit is obtained. This procedure constitutes a selection among methods regulated in advance for data reduction.
In the case of combination sensors, it is also known that communication of the sensor with a control unit or other system components may be handled via multichannel-capable interfaces or multiple separate interfaces. However, relatively large data volumes are transmitted to ensure a high detection reliability of states to be monitored.